I am running my page on PHP 5.2 that does not support CRYPT_BLOWFISH but CRYPT_MD5, and have heard that the blowfish is much more safer than md5. <
CRYPT_BLOWFISH
CRYPT_MD5
You can use PHPASS which has fallbacks to support systems that don't support CRYPT_BLOWFISH. Otherwise you can't really use bcrypt from PHP that I know of.